This invention relates to a vertical press for making dough beds for pizzas and the like food products from correspondingly apportioned lumps of the dough.
It is known that to prepare pizza beds on a commercial or near-commercial scale, vertical presses have long been used whereby an apportioned amount of an edible dough is pressed within a substantially pan-shaped die into a conforming shape. Special care and arrangements are applied to provide the moving plug on the press with such a structure and speed of advance as to enable the viscoelastic dough to acquire its desired shape without developing shreds or material discontinuities.
One such press is described, for instance, in Italian Patent No. 1,117,739, which provides a method of forming pizza beds using mechanical presses equipped with a press platen incorporating electric resistance heaters operative to bring it up to a suitably set temperature.
Another technical approach is disclosed in U.S. Pat. No. 4,511,324, which stresses the importance of preparing a dough sheet having a peripheral bead that can prevent condiments and fillings from flowing off as the pizza is being baked. A press is provided for the purpose wherein the moving plug is basically a plate formed with a peripheral bevel set at a suitable inclination angle to the rim of the die.
A third approach, disclosed in U.S. Pat. No. 4,303,677, is based on the preparation of a dough sheet having an upturned peripheral edge using first and second pressing steps to be carried out under different presses, the moving plug of the second press being designed and operated such as to form the upturned peripheral edge with substantially the same thickness as the remainder of the pizza bed.
The above-referenced prior approaches, while substantially achieving their objective of producing pizza beds on a commercial or near-commercial scale, share the disadvantage that they are unsuited to process as appropriate a dough which be intended for making genuine Neapolitan pizza.
It should be emphasized in this respect that the dough for a genuine Neapolitan pizza requires a characteristic amount of moisture (in the 55% to 70% range) and typical settle and rise times under appropriate conditions of temperature and humidity. For example, the dough settling time would usually be within the range of three to sixteen hours in an environment at a temperature between 20.degree. C. and 35.degree. C., depending on the amount of yeast in the dough.
A first settling period with concurrent rising of the entire body of dough is followed by forming into plural lumps, each to provide essentially a preform for subsequent processing into a corresponding pizza bed.
After a second, shorter, rising period, which may last between 30 and 90 minutes, such preforms appear as portions of a very supple dough, which are then kneaded manually by the pizza maker, using a characteristic skill not to be easily acquired, into an ultimate disk of varying thickness, being quite thin (0.5 mm) in its central region and thicker (3-6 mm) in its outward region around a peripheral edge.
This "manual" processing, applied by the pizza maker in a characteristic fashion, would vary between operatives, but is in all cases aimed at having the dough kneaded by pulling it from the center of the pizza bed toward the periphery thereof, leaving the texture of its outward edge virtually unaffected. During the kneading, this edge would locate inwards of the pulling hand palm. The pull applied to the dough along radial directions (or away from center) causes the carbon dioxide released through the dough by peripheral edge of the pizza bed is allowed thereby.
The underlying technical problem of this invention is to provide a press for preparing pizza beds on a commercial or near-commercial scale, which has such structural and functional features as to subject the preform to a dough stretching action along directions radiating from its center, with said stretching action being effective to displace the dough out from the preform center, rather than to just squeeze it, thereby the carbon dioxide generated within the dough during rise can build up in the thicker bed rim.